Remove StreamChannelTransformer.typed (dart-lang/stream_channel#44)

Closes dart-lang/stream_channel#41

I cannot find any uses of this and it can be replaced with a call to
`cast`.

pkgs/stream_channel/CHANGELOG.md

diff --git a/pkgs/stream_channel/CHANGELOG.md b/pkgs/stream_channel/CHANGELOG.md
index 8ebdc28..60400e0 100644
--- a/pkgs/stream_channel/CHANGELOG.md
+++ b/pkgs/stream_channel/CHANGELOG.md
@@ -8,6 +8,8 @@
   concerns due to importing `dart:isolate`.
 * Remove `JsonDocumentTransformer` class. The `jsonDocument` top level is still
   available.
+* Remove `StreamChannelTransformer.typed`. Use `.cast` on the transformed
+  channel instead.
 
 ## 1.7.0
 

pkgs/stream_channel/lib/src/stream_channel_transformer.dart

diff --git a/pkgs/stream_channel/lib/src/stream_channel_transformer.dart b/pkgs/stream_channel/lib/src/stream_channel_transformer.dart
index 32d36b6..cf62c76 100644
--- a/pkgs/stream_channel/lib/src/stream_channel_transformer.dart
+++ b/pkgs/stream_channel/lib/src/stream_channel_transformer.dart
@@ -8,7 +8,6 @@
 import 'package:async/async.dart';
 
 import '../stream_channel.dart';
-import 'transformer/typed.dart';
 
 /// A [StreamChannelTransformer] transforms the events being passed to and
 /// emitted by a [StreamChannel].
@@ -32,21 +31,6 @@
   /// The transformer to use on the channel's sink.
   final StreamSinkTransformer<S, T> _sinkTransformer;
 
-  /// Creates a wrapper that coerces the type of [transformer].
-  ///
-  /// This soundly converts a [StreamChannelTransformer] to a
-  /// `StreamChannelTransformer<S, T>`, regardless of its original generic type,
-  /// by asserting that the events emitted by the transformed channel's stream
-  /// are instances of `T` whenever they're provided. If they're not, the stream
-  /// throws a [CastError]. This also means that calls to [StreamSink.add] on
-  /// the transformed channel's sink may throw a [CastError] if the argument
-  /// type doesn't match the reified type of the sink.
-  static StreamChannelTransformer<S, T> typed<S, T>(
-          StreamChannelTransformer transformer) =>
-      transformer is StreamChannelTransformer<S, T>
-          ? transformer
-          : TypeSafeStreamChannelTransformer(transformer);
-
   /// Creates a [StreamChannelTransformer] from existing stream and sink
   /// transformers.
   const StreamChannelTransformer(

pkgs/stream_channel/lib/src/transformer/typed.dart

diff --git a/pkgs/stream_channel/lib/src/transformer/typed.dart b/pkgs/stream_channel/lib/src/transformer/typed.dart
deleted file mode 100644
index 875cdac..0000000
--- a/pkgs/stream_channel/lib/src/transformer/typed.dart
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import '../../stream_channel.dart';
-
-/// A wrapper that coerces the generic type of the channel returned by an inner
-/// transformer to `S`.
-class TypeSafeStreamChannelTransformer<S, T>
-    implements StreamChannelTransformer<S, T> {
-  final StreamChannelTransformer _inner;
-
-  TypeSafeStreamChannelTransformer(this._inner);
-
-  @override
-  StreamChannel<S> bind(StreamChannel<T> channel) =>
-      _inner.bind(channel).cast();
-}